Gross primary production(GPP)is a crucial indicator representing the absorption of atmospheric CO_(2) by vegetation.At present,the estimation of GPP by remote sensing is mainly based on leaf-related vegetation indexes...Gross primary production(GPP)is a crucial indicator representing the absorption of atmospheric CO_(2) by vegetation.At present,the estimation of GPP by remote sensing is mainly based on leaf-related vegetation indexes and leaf-related biophysical para-meter leaf area index(LAI),which are not completely synchronized in seasonality with GPP.In this study,we proposed chlorophyll content-based light use efficiency model(CC-LUE)to improve GPP estimates,as chlorophyll is the direct site of photosynthesis,and only the light absorbed by chlorophyll is used in the photosynthetic process.The CC-LUE model is constructed by establishing a linear correlation between satellite-derived canopy chlorophyll content(Chlcanopy)and FPAR.This method was calibrated and validated utiliz-ing 7-d averaged in-situ GPP data from 14 eddy covariance flux towers covering deciduous broadleaf forest ecosystems across five dif-ferent climate zones.Results showed a relatively robust seasonal consistency between Chlcanopy with GPP in deciduous broadleaf forests under different climatic conditions.The CC-LUE model explained 88% of the in-situ GPP seasonality for all validation site-year and 56.0% of in-situ GPP variations through the growing season,outperforming the three widely used LUE models(MODIS-GPP algorithm,Vegetation Photosynthesis Model(VPM),and the eddy covariance-light use efficiency model(EC-LUE)).Additionally,the CC-LUE model(RMSE=0.50 g C/(m^(2)·d))significantly improved the underestimation of GPP during the growing season in semi-arid region,re-markably decreasing the root mean square error of averaged growing season GPP simulation and in-situ GPP by 75.4%,73.4%,and 37.5%,compared with MOD17(RMSE=2.03 g C/(m^(2)·d)),VPM(RMSE=1.88 g C/(m^(2)·d)),and EC-LUE(RMSE=0.80 g C/(m^(2)·d))model.The chlorophyll-based method proved superior in capturing the seasonal variations of GPP in forest ecosystems,thereby provid-ing the possibility of a more precise depiction of forest seasonal carbon uptake.展开更多
Gross primary productivity(GPP)of vegetation is an important constituent of the terrestrial carbon sinks and is significantly influenced by drought.Understanding the impact of droughts on different types of vegetation...Gross primary productivity(GPP)of vegetation is an important constituent of the terrestrial carbon sinks and is significantly influenced by drought.Understanding the impact of droughts on different types of vegetation GPP provides insight into the spatiotemporal variation of terrestrial carbon sinks,aiding efforts to mitigate the detrimental effects of climate change.In this study,we utilized the precipitation and temperature data from the Climatic Research Unit,the standardized precipitation evapotranspiration index(SPEI),the standardized precipitation index(SPI),and the simulated vegetation GPP using the eddy covariance-light use efficiency(EC-LUE)model to analyze the spatiotemporal change of GPP and its response to different drought indices in the Mongolian Plateau during 1982-2018.The main findings indicated that vegetation GPP decreased in 50.53% of the plateau,mainly in its northern and northeastern parts,while it increased in the remaining 49.47%area.Specifically,meadow steppe(78.92%)and deciduous forest(79.46%)witnessed a significant decrease in vegetation GPP,while alpine steppe(75.08%),cropland(76.27%),and sandy vegetation(87.88%)recovered well.Warming aridification areas accounted for 71.39% of the affected areas,while 28.53% of the areas underwent severe aridification,mainly located in the south and central regions.Notably,the warming aridification areas of desert steppe(92.68%)and sandy vegetation(90.24%)were significant.Climate warming was found to amplify the sensitivity of coniferous forest,deciduous forest,meadow steppe,and alpine steppe GPP to drought.Additionally,the drought sensitivity of vegetation GPP in the Mongolian Plateau gradually decreased as altitude increased.The cumulative effect of drought on vegetation GPP persisted for 3.00-8.00 months.The findings of this study will improve the understanding of how drought influences vegetation in arid and semi-arid areas.展开更多
BACKGROUND To retrospectively report the safety and efficacy of renal transcatheter arterial embolization for treating autosomal dominant polycystic kidney disease(ADPKD)patients with gross hematuria.CASE SUMMARY The ...BACKGROUND To retrospectively report the safety and efficacy of renal transcatheter arterial embolization for treating autosomal dominant polycystic kidney disease(ADPKD)patients with gross hematuria.CASE SUMMARY The purpose of this study is to retrospectively report the safety and efficacy of renal transcatheter arterial embolization for treating ADPKD patients with gross hematuria.Materials and methods:During the period from January 2018 to December 2019,renal transcatheter arterial embolization was carried out on 6 patients with polycystic kidneys and gross hematuria.Renal arteriography was performed first,and then we determined the location of the hemorrhage and performed embolization under digital subtraction angiography monitoring.Improvements in routine blood test results,routine urine test results,urine color and postoperative reactions were observed and analyzed.Results:Renal transcatheter arterial embolization was successfully conducted in 6 patients.The indices of 5 patients and the color of gross hematuria improved after surgery compared with before surgery.No severe complication reactions occurred.CONCLUSION For autosomal dominant polycystic kidney syndrome patients with gross hematuria,transcatheter arterial embolization was safe and effective.展开更多
Objective: To investigate the effect of VOJTA therapy on gross motor function in children with cerebral palsy. Methods: The 86 children with cerebral palsy were all from the First People’s Hospital of Jingzhou City f...Objective: To investigate the effect of VOJTA therapy on gross motor function in children with cerebral palsy. Methods: The 86 children with cerebral palsy were all from the First People’s Hospital of Jingzhou City from January 2023-December 2023, and were divided into the control group and the study group with 43 cases according to the principle of voluntariness. Results: In terms of total effective rate of treatment, the gross motor function scale-88 (GMFM-88) was used to evaluate the effective rate before and after treatment, and the effective rate of the study group was higher than that of the control group, and the difference was statistically significant, and the scores of gross motor items of GMFM-88 were better than those of the control group after treatment, and the difference was statistically significant (P 0.05). Conclusion: The application of VOJTA therapy in the treatment of children with cerebral palsy can not only promote the rehabilitation of gross motor function, but also help to improve the treatment effect, and the earlier the treatment, the better.展开更多
Drinking good quality water is essential for better health. It is therefore essential to assess the radiological quality of all water consumed in the District of Abidjan in order to prevent related hazards. Thus, the ...Drinking good quality water is essential for better health. It is therefore essential to assess the radiological quality of all water consumed in the District of Abidjan in order to prevent related hazards. Thus, the objective of this study was to assess the risk of cancer due to the ingestion of alpha and beta emitting radionuclides in the different types of water consumed in the region. A total of 63 water samples with 43 tap water samples, 5 bottled mineral water and 15 sachet water samples was collected and taken to GAEC laboratory for analysis. The low background Gas-less Automatic Alpha/Beta counting system (Canberra iMatic<sup>TM</sup>) was used to determine alpha and beta activity concentrations. Activity concentrations of both gross alpha and gross beta obtained in water sample were respectively lower than the WHO recommended limits of 0.1 Bq/l and 1 Bq/l. Also, the annual effective dose and total equivalent effective dose found in mineral bottled water samples were higher than in other types of water. The assessment of radiological lifetime risk has shown values of cancer risk due to ingestion alpha and beta emitters lower than recommended limit. These results indicate that there is no health hazard associated to consumption of water in the District of Abidjan.展开更多
近年来,随着中国经济的稳定发展,居民可支配收入的不断提高,人们在满足基本生活需要的前提下,也在不断地追求着个性化的消费。潮流玩具盲盒凭借着其未知性和稀有性一夜爆火。面对新的行业、新的市场,如何才能更好地抓住消费者的需求并...近年来,随着中国经济的稳定发展,居民可支配收入的不断提高,人们在满足基本生活需要的前提下,也在不断地追求着个性化的消费。潮流玩具盲盒凭借着其未知性和稀有性一夜爆火。面对新的行业、新的市场,如何才能更好地抓住消费者的需求并明确未来的发展方向,是潮流玩具企业急需考虑的问题。本文在整理总结前人的研究基础上,以Sheth-Newman-Gross的消费者价值理论为支撑,构建了泡泡玛特公司盲盒产品的消费者购买行为模型,以消费价值划分的五个维度即功能价值、社会价值、情感价值、认知价值、条件价值设计观察变量,探索盲盒产品消费价值里的哪些因素对购买行为有显著相关性,从而为该公司营销策略优化改进提出可行性建议。研究结果表明:功能价值、社会价值、情感价值对购买行为有显著的正向影响,认知价值和条件价值对购买行为的影响并不显著。根据研究结论,虽然本文所提的建议主要是针对泡泡玛特公司的营销策略,但也可以推广到有相似发展模式的行业,这对于其他行业的发展有很大的借鉴意义。In recent years, with the stable development of the Chinese economy and the continuous increase in disposable income of residents, people have been pursuing personalized consumption while meeting their basic living needs. The trendy toy blind box went viral overnight due to its unknown and rare nature. Facing new industries and markets, how to better grasp consumer needs and clarify future development directions is an urgent issue that trendy toy companies need to consider. Based on the summary of previous research and supported by Sheth Newman Gross’s consumer value theory, this article constructs a consumer purchasing behavior model for blind box products of POP Mart Company. Using five dimensions of consumer value, namely functional value, social value, emotional value, cognitive value, and conditional value, observation variables are designed to explore which factors in the consumption value of blind box products are significantly correlated with purchasing behavior, and to provide feasible suggestions for optimizing and improving the company’s marketing strategy. The research results indicate that functional value, social value, and emotional value have a significant positive impact on purchasing behavior, while cognitive value and conditional value have no significant impact on purchasing behavior. According to the research conclusion, although the suggestions proposed in this article are mainly aimed at the marketing strategy of POP Mart Company, they can also be extended to industries with similar development models, which has great reference significance for the development of other industries.展开更多
This paper describes a low-cost and fast method to evaluate gross α and β^(-) radioactivities in natural water based on an online high-purity germanium detector gamma measurement system.The major gamma activities in...This paper describes a low-cost and fast method to evaluate gross α and β^(-) radioactivities in natural water based on an online high-purity germanium detector gamma measurement system.The major gamma activities in natural water are provided by natural and artificial radionuclides such as ^(40) K,^(137)Cs,and radionuclides belonging to ^(238)U and ^(232)Th series.The main a emitters related to gamma emissions in natural water are ^(224)Ra(240.98 keV)and ^(226)Ra(186.21 keV),and the β^(-) emitters are ^(40) K(1460.85 keV),^(214)Bi(609.31 keV),^(208)Tl(583.19 keV),and ^(214)Pb(351.93 keV).The formula for gross α and β^(-) activity concentration is based on these radionuclides,and the short half-life decay products are considered in the calculation.The detection efficiency of the device across energy region(0–3 MeV)is obtained through Monte Carlo simulation,and a calibration experiment is conducted to verify the simulation results.Gamma radioactivity is measured continuously for 114 d in Pixian County and Dongfeng Canal located in the Zouma River,Chengdu,Sichuan Province,China.A comparison of the calculation results and monitoring data from the Sichuan Management and Monitoring Center Station of Radioactive Environment indicates that the percentage and absolute error of a activity concentration is lower than 53%and 0.02 Bq/L,respectively,and that of β-activity concentration is lower than 33.2%and 0.016 Bq/L,respectively.The method can rapidly determine gross α and β^(-) activity concentrations in natural water online.展开更多
This paper presents a novel approach to identify and correct the gross errors in the microelectromechanical system （MEMS） gyroscope used in ground vehicles by means of time series analysis. According to the characte...This paper presents a novel approach to identify and correct the gross errors in the microelectromechanical system （MEMS） gyroscope used in ground vehicles by means of time series analysis. According to the characteristics of autocorrelation function （ACF） and partial autocorrelation function （PACF）, an autoregressive integrated moving average （ARIMA） model is roughly constructed. The rough model is optimized by combining with Akaike＇s information criterion （A/C）, and the parameters are estimated based on the least squares algorithm. After validation testing, the model is utilized to forecast the next output on the basis of the previous measurement. When the difference between the measurement and its prediction exceeds the defined threshold, the measurement is identified as a gross error and remedied by its prediction. A case study on the yaw rate is performed to illustrate the developed algorithm. Experimental results demonstrate that the proposed approach can effectively distinguish gross errors and make some reasonable remedies.展开更多
Objective: To study the accuracy between CT and MRI in delineating gross tumor volume (GTV) of nasopharyngeal carcinoma (NPC) in making radiotherapy plan. Methods: The clinical data of 39 cases pathologically proven a...Objective: To study the accuracy between CT and MRI in delineating gross tumor volume (GTV) of nasopharyngeal carcinoma (NPC) in making radiotherapy plan. Methods: The clinical data of 39 cases pathologically proven as nasopharyngeal carcinoma selected from April 2003 to September 2004 were retrospectively analyzed. All were subjected to CT and MR examination one week before treatment. CT scanning was performed with GE Light speed 16, and axial scan was parallel to the OM line routinely from soft palate to the suprasellar cistern. MR scanning was performed by GE Signa super-conducting magnetic resonance imaging system (1.5 Tesla). The standard quadrature head coil was used. Routine axial, sagittal and coronal image with SE sequence were obtained, and FLAIR was used in 10 of 21 cases. Scanned field ranged from the soft palate to the suprasellar cistern. Part of all cases underwent enhanced scanned with Ultravist in CT group or/and GD-DTPA in MR group. All data were analyzed by using the paired-samples t test. Results: The media primary tumor volume (cm3) in CT group and MR group was 32.49±19.91, 29.06±18.75, respectively, and the difference between the two groups were significant (t=5.268, P=0.000). There was significant difference between the two groups in early stage (T1+T2) and advanced stage (T3+T4) by Fuzhou Staging System (t=5.677, P=0.000; t=3.310, P=0.005, respectively). There was significant difference in stage T1, T2, T3 (P=0.005, P=0.001, P=0.004, respectively), and not in stage T4 (P=0.146) between the two groups. Conclusion: MR was more accurate than CT in delineating GTV of NPC, so, is more valuable in making radiotherapy plan.展开更多
基金Under the auspices of the National Key Research and Development Program of China(No.2019YFA0606603)。
文摘Gross primary production(GPP)is a crucial indicator representing the absorption of atmospheric CO_(2) by vegetation.At present,the estimation of GPP by remote sensing is mainly based on leaf-related vegetation indexes and leaf-related biophysical para-meter leaf area index(LAI),which are not completely synchronized in seasonality with GPP.In this study,we proposed chlorophyll content-based light use efficiency model(CC-LUE)to improve GPP estimates,as chlorophyll is the direct site of photosynthesis,and only the light absorbed by chlorophyll is used in the photosynthetic process.The CC-LUE model is constructed by establishing a linear correlation between satellite-derived canopy chlorophyll content(Chlcanopy)and FPAR.This method was calibrated and validated utiliz-ing 7-d averaged in-situ GPP data from 14 eddy covariance flux towers covering deciduous broadleaf forest ecosystems across five dif-ferent climate zones.Results showed a relatively robust seasonal consistency between Chlcanopy with GPP in deciduous broadleaf forests under different climatic conditions.The CC-LUE model explained 88% of the in-situ GPP seasonality for all validation site-year and 56.0% of in-situ GPP variations through the growing season,outperforming the three widely used LUE models(MODIS-GPP algorithm,Vegetation Photosynthesis Model(VPM),and the eddy covariance-light use efficiency model(EC-LUE)).Additionally,the CC-LUE model(RMSE=0.50 g C/(m^(2)·d))significantly improved the underestimation of GPP during the growing season in semi-arid region,re-markably decreasing the root mean square error of averaged growing season GPP simulation and in-situ GPP by 75.4%,73.4%,and 37.5%,compared with MOD17(RMSE=2.03 g C/(m^(2)·d)),VPM(RMSE=1.88 g C/(m^(2)·d)),and EC-LUE(RMSE=0.80 g C/(m^(2)·d))model.The chlorophyll-based method proved superior in capturing the seasonal variations of GPP in forest ecosystems,thereby provid-ing the possibility of a more precise depiction of forest seasonal carbon uptake.
基金jointly supported by the National Natural Science Foundation of China(42361024,42101030,42261079,and 41961058)the Talent Project of Science and Technology in Inner Mongolia of China(NJYT22027 and NJYT23019)the Fundamental Research Funds for the Inner Mongolia Normal University,China(2022JBBJ014 and 2022JBQN093)。
文摘Gross primary productivity(GPP)of vegetation is an important constituent of the terrestrial carbon sinks and is significantly influenced by drought.Understanding the impact of droughts on different types of vegetation GPP provides insight into the spatiotemporal variation of terrestrial carbon sinks,aiding efforts to mitigate the detrimental effects of climate change.In this study,we utilized the precipitation and temperature data from the Climatic Research Unit,the standardized precipitation evapotranspiration index(SPEI),the standardized precipitation index(SPI),and the simulated vegetation GPP using the eddy covariance-light use efficiency(EC-LUE)model to analyze the spatiotemporal change of GPP and its response to different drought indices in the Mongolian Plateau during 1982-2018.The main findings indicated that vegetation GPP decreased in 50.53% of the plateau,mainly in its northern and northeastern parts,while it increased in the remaining 49.47%area.Specifically,meadow steppe(78.92%)and deciduous forest(79.46%)witnessed a significant decrease in vegetation GPP,while alpine steppe(75.08%),cropland(76.27%),and sandy vegetation(87.88%)recovered well.Warming aridification areas accounted for 71.39% of the affected areas,while 28.53% of the areas underwent severe aridification,mainly located in the south and central regions.Notably,the warming aridification areas of desert steppe(92.68%)and sandy vegetation(90.24%)were significant.Climate warming was found to amplify the sensitivity of coniferous forest,deciduous forest,meadow steppe,and alpine steppe GPP to drought.Additionally,the drought sensitivity of vegetation GPP in the Mongolian Plateau gradually decreased as altitude increased.The cumulative effect of drought on vegetation GPP persisted for 3.00-8.00 months.The findings of this study will improve the understanding of how drought influences vegetation in arid and semi-arid areas.
文摘BACKGROUND To retrospectively report the safety and efficacy of renal transcatheter arterial embolization for treating autosomal dominant polycystic kidney disease(ADPKD)patients with gross hematuria.CASE SUMMARY The purpose of this study is to retrospectively report the safety and efficacy of renal transcatheter arterial embolization for treating ADPKD patients with gross hematuria.Materials and methods:During the period from January 2018 to December 2019,renal transcatheter arterial embolization was carried out on 6 patients with polycystic kidneys and gross hematuria.Renal arteriography was performed first,and then we determined the location of the hemorrhage and performed embolization under digital subtraction angiography monitoring.Improvements in routine blood test results,routine urine test results,urine color and postoperative reactions were observed and analyzed.Results:Renal transcatheter arterial embolization was successfully conducted in 6 patients.The indices of 5 patients and the color of gross hematuria improved after surgery compared with before surgery.No severe complication reactions occurred.CONCLUSION For autosomal dominant polycystic kidney syndrome patients with gross hematuria,transcatheter arterial embolization was safe and effective.
文摘Objective: To investigate the effect of VOJTA therapy on gross motor function in children with cerebral palsy. Methods: The 86 children with cerebral palsy were all from the First People’s Hospital of Jingzhou City from January 2023-December 2023, and were divided into the control group and the study group with 43 cases according to the principle of voluntariness. Results: In terms of total effective rate of treatment, the gross motor function scale-88 (GMFM-88) was used to evaluate the effective rate before and after treatment, and the effective rate of the study group was higher than that of the control group, and the difference was statistically significant, and the scores of gross motor items of GMFM-88 were better than those of the control group after treatment, and the difference was statistically significant (P 0.05). Conclusion: The application of VOJTA therapy in the treatment of children with cerebral palsy can not only promote the rehabilitation of gross motor function, but also help to improve the treatment effect, and the earlier the treatment, the better.
文摘Drinking good quality water is essential for better health. It is therefore essential to assess the radiological quality of all water consumed in the District of Abidjan in order to prevent related hazards. Thus, the objective of this study was to assess the risk of cancer due to the ingestion of alpha and beta emitting radionuclides in the different types of water consumed in the region. A total of 63 water samples with 43 tap water samples, 5 bottled mineral water and 15 sachet water samples was collected and taken to GAEC laboratory for analysis. The low background Gas-less Automatic Alpha/Beta counting system (Canberra iMatic<sup>TM</sup>) was used to determine alpha and beta activity concentrations. Activity concentrations of both gross alpha and gross beta obtained in water sample were respectively lower than the WHO recommended limits of 0.1 Bq/l and 1 Bq/l. Also, the annual effective dose and total equivalent effective dose found in mineral bottled water samples were higher than in other types of water. The assessment of radiological lifetime risk has shown values of cancer risk due to ingestion alpha and beta emitters lower than recommended limit. These results indicate that there is no health hazard associated to consumption of water in the District of Abidjan.
文摘近年来,随着中国经济的稳定发展,居民可支配收入的不断提高,人们在满足基本生活需要的前提下,也在不断地追求着个性化的消费。潮流玩具盲盒凭借着其未知性和稀有性一夜爆火。面对新的行业、新的市场,如何才能更好地抓住消费者的需求并明确未来的发展方向,是潮流玩具企业急需考虑的问题。本文在整理总结前人的研究基础上,以Sheth-Newman-Gross的消费者价值理论为支撑,构建了泡泡玛特公司盲盒产品的消费者购买行为模型,以消费价值划分的五个维度即功能价值、社会价值、情感价值、认知价值、条件价值设计观察变量,探索盲盒产品消费价值里的哪些因素对购买行为有显著相关性,从而为该公司营销策略优化改进提出可行性建议。研究结果表明:功能价值、社会价值、情感价值对购买行为有显著的正向影响,认知价值和条件价值对购买行为的影响并不显著。根据研究结论,虽然本文所提的建议主要是针对泡泡玛特公司的营销策略,但也可以推广到有相似发展模式的行业,这对于其他行业的发展有很大的借鉴意义。In recent years, with the stable development of the Chinese economy and the continuous increase in disposable income of residents, people have been pursuing personalized consumption while meeting their basic living needs. The trendy toy blind box went viral overnight due to its unknown and rare nature. Facing new industries and markets, how to better grasp consumer needs and clarify future development directions is an urgent issue that trendy toy companies need to consider. Based on the summary of previous research and supported by Sheth Newman Gross’s consumer value theory, this article constructs a consumer purchasing behavior model for blind box products of POP Mart Company. Using five dimensions of consumer value, namely functional value, social value, emotional value, cognitive value, and conditional value, observation variables are designed to explore which factors in the consumption value of blind box products are significantly correlated with purchasing behavior, and to provide feasible suggestions for optimizing and improving the company’s marketing strategy. The research results indicate that functional value, social value, and emotional value have a significant positive impact on purchasing behavior, while cognitive value and conditional value have no significant impact on purchasing behavior. According to the research conclusion, although the suggestions proposed in this article are mainly aimed at the marketing strategy of POP Mart Company, they can also be extended to industries with similar development models, which has great reference significance for the development of other industries.
基金the National Science Foundation of China(No.41774147)the National Key R&D Program of China(No.2017YFC0602105)+1 种基金the Science–Technology Support Plan Projects of Sichuan Province(No.2020YJ0334)the Sichuan Science and Technology Program(No.2020JDRC0108).
文摘This paper describes a low-cost and fast method to evaluate gross α and β^(-) radioactivities in natural water based on an online high-purity germanium detector gamma measurement system.The major gamma activities in natural water are provided by natural and artificial radionuclides such as ^(40) K,^(137)Cs,and radionuclides belonging to ^(238)U and ^(232)Th series.The main a emitters related to gamma emissions in natural water are ^(224)Ra(240.98 keV)and ^(226)Ra(186.21 keV),and the β^(-) emitters are ^(40) K(1460.85 keV),^(214)Bi(609.31 keV),^(208)Tl(583.19 keV),and ^(214)Pb(351.93 keV).The formula for gross α and β^(-) activity concentration is based on these radionuclides,and the short half-life decay products are considered in the calculation.The detection efficiency of the device across energy region(0–3 MeV)is obtained through Monte Carlo simulation,and a calibration experiment is conducted to verify the simulation results.Gamma radioactivity is measured continuously for 114 d in Pixian County and Dongfeng Canal located in the Zouma River,Chengdu,Sichuan Province,China.A comparison of the calculation results and monitoring data from the Sichuan Management and Monitoring Center Station of Radioactive Environment indicates that the percentage and absolute error of a activity concentration is lower than 53%and 0.02 Bq/L,respectively,and that of β-activity concentration is lower than 33.2%and 0.016 Bq/L,respectively.The method can rapidly determine gross α and β^(-) activity concentrations in natural water online.
基金The National Natural Science Foundation of China(No.61273236)the Natural Science Foundation of Jiangsu Province(No.BK2010239)the Ph.D.Programs Foundation of Ministry of Education of China(No.200802861061)
文摘This paper presents a novel approach to identify and correct the gross errors in the microelectromechanical system （MEMS） gyroscope used in ground vehicles by means of time series analysis. According to the characteristics of autocorrelation function （ACF） and partial autocorrelation function （PACF）, an autoregressive integrated moving average （ARIMA） model is roughly constructed. The rough model is optimized by combining with Akaike＇s information criterion （A/C）, and the parameters are estimated based on the least squares algorithm. After validation testing, the model is utilized to forecast the next output on the basis of the previous measurement. When the difference between the measurement and its prediction exceeds the defined threshold, the measurement is identified as a gross error and remedied by its prediction. A case study on the yaw rate is performed to illustrate the developed algorithm. Experimental results demonstrate that the proposed approach can effectively distinguish gross errors and make some reasonable remedies.
基金This work was supported by a grant from the National Natural Science Foundation of China (No. 30470525).
文摘Objective: To study the accuracy between CT and MRI in delineating gross tumor volume (GTV) of nasopharyngeal carcinoma (NPC) in making radiotherapy plan. Methods: The clinical data of 39 cases pathologically proven as nasopharyngeal carcinoma selected from April 2003 to September 2004 were retrospectively analyzed. All were subjected to CT and MR examination one week before treatment. CT scanning was performed with GE Light speed 16, and axial scan was parallel to the OM line routinely from soft palate to the suprasellar cistern. MR scanning was performed by GE Signa super-conducting magnetic resonance imaging system (1.5 Tesla). The standard quadrature head coil was used. Routine axial, sagittal and coronal image with SE sequence were obtained, and FLAIR was used in 10 of 21 cases. Scanned field ranged from the soft palate to the suprasellar cistern. Part of all cases underwent enhanced scanned with Ultravist in CT group or/and GD-DTPA in MR group. All data were analyzed by using the paired-samples t test. Results: The media primary tumor volume (cm3) in CT group and MR group was 32.49±19.91, 29.06±18.75, respectively, and the difference between the two groups were significant (t=5.268, P=0.000). There was significant difference between the two groups in early stage (T1+T2) and advanced stage (T3+T4) by Fuzhou Staging System (t=5.677, P=0.000; t=3.310, P=0.005, respectively). There was significant difference in stage T1, T2, T3 (P=0.005, P=0.001, P=0.004, respectively), and not in stage T4 (P=0.146) between the two groups. Conclusion: MR was more accurate than CT in delineating GTV of NPC, so, is more valuable in making radiotherapy plan.
